[PATCH] libgloss/riscv: Fix hard coded reference to configure.in after rename

The file configure.in was renamed to configure.ac in libgloss/riscv but
the hard coded name in the Makefile for that directory was not updated.
This patch simply renamed this to configure.ac.
---
 libgloss/riscv/Makefile.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libgloss/riscv/Makefile.in b/libgloss/riscv/Makefile.in
index 185b6e6d2..d118a1876 100644
--- a/libgloss/riscv/Makefile.in
+++ b/libgloss/riscv/Makefile.in
@@ -306,7 +306,7 @@ install : install-hdrs install-libs install-specs
 #-------------------------------------------------------------------------
 
 configure_prereq = \
-  $(src_dir)/configure.in \
+  $(src_dir)/configure.ac \
 
 $(src_dir)/configure : $(configure_prereq)
 	cd $(src_dir) && autoconf
-- 
2.25.1